The company said the service began "with a pledge to increase on-time performance and improve safety, cleanliness, and customer service."

Keolis Commuter Services, part of Keolis North America, bid and won a $2.6 billion, eight-year contract last January to to operate and maintain MBTA service, serving 127,000 riders daily. MBTA service previously had been operated by Veolia Transportation, Inc.

"This is a momentous day for Keolis, our passengers and the communities we will serve," said Keolis North America Executive Vice President Eric Asselin. "From customer service to on-time performance, we pride ourselves in how we are always 'thinking like a passenger' in everything we do. With the commitment of our employees and the input of our passengers, we are dedicated to making one of the nation's preeminent commuter rail services even better."

Keolis officials said passengers will begin to see changes designed to improve their travel experience almost immediately, among them the launch of a staffed customer service center that will be open seven days a week to provide assistance to customers. Passengers will also be encouraged to share suggestions or concerns via a dedicated customer service Twitter account @MBTA_CR and on Facebook.

Other improvements will include freshly cleaned trains and stations, new signage, and repairs to damaged seats. New pocket timetables, featuring larger, easier-to-read system maps, are distributing today at the major stations.

Keolis will also be introducing the first official MBTA Commuter Rail app which is designed to make it easier for passengers to plan their journey. The first version of the app was released Tuesday, and is free and available for download for both Apple and Android devices. An enhanced version will be released this fall, providing real-time information about rail travel times, a place to register lost or found items in trains and stations, and other features designed to enhance the passenger experience.